Read manga: Saikawa Fusai No Renai Jijou - Nananen Jikkuri

manga
Summary:

[from cotton candy scans]He’s super doting at work but sadistic when in private; the true nature of my colleague who’s great at his job is... Hanamura Mitsuki and Saikawa Chiaki, age 29, both work at an advertising firm. They’re called the “Saikawa Married Couple” by everyone around them because of the way they work in perfect synchrony after being together for so long. Even though they’re totally different in private, Saikawa-kun intentionally gave her a deep kiss in front of everyone at a drinking party. Mitsuki, who doesn’t understand his true feelings and is just being toyed around with, can’t help but feel distressed...?!